Pentaborane, a boron hydride, is a propellant that has been used as a rocket fuel additive for air-breathing engines. Accordingly, pentaborane has found utility in rockets, missiles and military jet aircraft. Because of its extremely toxic and pyrophoric nature, it is widely recognized that pentaborane must be handled with extreme caution.
Pentaborane, which may be represented by the chemical formulation "B.sub.5 H.sub.9 " (or "B.sub.5 H.sub.11 " in its unstable state), is an extremely dangerous material. It is typically a colorless liquid or gas that is highly toxic to humans by ingestion, skin contact or inhalation. For example, ingestion or inhalation of even a very small amount of pentaborane, on the order of five parts per million (5 ppm), is likely fatal and at least sufficient to cause severe distress to humans. The toxicity of pentaborane is comparable to that of chemical warfare nerve agents. Moreover, pentaborane is highly pyrophoric in air. Accordingly, there is not only a danger to anyone that must handle pentaborane, there is also an extreme danger of fire or explosion in handling pentaborane. Pentaborane is understandably listed as an "extremely hazardous substance" under Section 302 of the Superfund Amendments and Reauthorization Act ("SARA").
Yet further, while pentaborane is traditionally provided in a liquid state, liquid pentaborane evaporates rapidly and becomes gaseous at ambient, room temperature. Pentaborane is therefore oftentimes stored in cylinders or containers that secure the material and prevent its introduction to air. The cylinders are oftentimes stored in relatively cool environments such as underground facilities or bunkers. The containers are oftentimes of significant size. For example, it is not unusual to store pure pentaborane in a three hundred pound (300 lb.) container. With the pentaborane stored therein, the container and material may weigh as much as eight-hundred pounds (800 lbs.).
Pentaborane containers may sometimes be stored for significant periods of time, perhaps resulting in deterioration of the cylinder. In such an event, the cylinder must be emptied and purged of the pentaborane. Moreover, it has become desirable to dispose of certain quantities of pentaborane. Once again, in order to effect such disposal, the cylinders must be emptied and purged of the pentaborane. Given that pentaborane is colorless, flammable and extremely toxic even in very small amounts, such disposal is difficult.
A variety of attempts have been made in the past to dispose of pure pentaborane stocks. Due to the extremely difficult nature of handling the material, it has sometimes been found necessary to detonate a cylinder containing pentaborane rather than attempt to vent the pentaborane and treat it chemically. An example of one such effort that resulted from a failed cylinder is described in detail in a document entitled "Pentaborane Release Environmental Laboratories Hanover County Va, National Response Team Briefing, March 1982." This reference describes the difficulty experienced with a failed cylinder and the need to destroy the container. Other articles have been written detailing the dangerous nature of pentaborane and handling this material. See, for example, Silverman, J. J., et al., Post Traumatic Stress Disorder From Pentaborane Intoxication, JAMA 254 (18), 2603-2608 (1985).
Yet another article resulting from the Hanover County Pentaborane Release was published in "Fire Engineering" authored by the Hanover County, Virginia Fire Department Chief. This article detailed the dangerous nature of both the pentaborane and the destruction of the cylinder. As described therein, one major concern of the workers charged with the responsibility of disposing of the cylinder was the need to transport the failed cylinder from the location of the accident to another location where the cylinder could be destroyed. Of course, such transportation involves inherent risks to the general public as well as those directly involved in transporting the cylinder. The movement of such a hazardous material understandably involves and concerns a variety of state and federal environmental regulatory persons, depending on the particular circumstances. Even if the pentaborane container is in good condition, the catastrophic consequences of an in-transit accident render shipment of the cylinder difficult, costly and effectively unfeasible.
Thus, as shown by circumstances and instances of human exposure to pentaborane, there exists a need in the art to provide a systematic method and apparatus by which to dispose of pentaborane in a safe and efficient manner. Further, it would be preferable that any such method and apparatus be capable of handling and treating the pentaborane cylinder or other container on site, at the location where the cylinder or container is found. Moreover, because pentaborane is so toxic to humans, the preferred method and apparatus could be operated remotely without an operator being proximate to the cylinder or container. Such a remotely operated method and apparatus would preferably permit the operator to sense or detect the presence of any pentaborane, analyze the contents of the cylinder and any part of the apparatus for pentaborane and its treatment, and monitor the apparatus from a safe distance.